Road Distance Database

Notice

The Google Maps travel route shown is for display purposes only. In certain circumstances the route shown may differ from the route calculated by the Newfoundland and Labrador Statistics Agency to produce distances and travel times. For more information please contact the Newfoundland and Labrador Statistics Agency.

Purpose

The Social and Economic Analysis Unit of the Newfoundland & Labrador Statistics Agency created the Newfoundland & Labrador Road Distance Database
(NL-RDDb) to give users approximate road distances and travel times between places in Newfoundland & Labrador.
Although the database was created to examine distances between communities for
spatial analysis, it has become a valued resource for travel
planning.

Assumptions

The needs of the varied target audience require a differentiation between absolute distances and travel time between two selected communities.
Where two routes are possible the route via automobile travel takes precedence over a passenger ferry option. These two measures are considered 'costs'
and the choice will vary by application.

Caveats

The database offers two solutions using two sets of criteria. The distances solution is the ‘shortest network path’ in absolute minimum distances given the existing road network. The ‘travel time’ is calculated as minimums but by using the cumulative times of traversing the road segments at the established rate of speed. Thus, there is no assurance that the least distance route is the same route used to determine the least travel time.
For example, the absolute minimum distance between Placentia and St. John’s is 126 kilometers via Colinet and Salmonier Line. The minimum travel time is via the more popular Whitbourne –TCH. This is a case where it takes a shorter time to travel a longer distance because of a faster rate of travel. These cases are relatively few.
The ferry system can affect assumptions made by end-users. Several ferry routes are restricted to pedestrian passengers. This becomes an issue in cases of travel between communities on the Burin Peninsula and communities on the Connaigre Peninsula (Harbour Breton area).
The passenger ferry service from Bay L’Argent and Pool’s Cove provides the shortest distance and time but the automobile option is considerably longer requiring travel to Grand Falls-Windsor and then south on the Bay D’Espoir Highway (Route 360).
In such cases, barriers have been added to the road network to ensure the
automobile option is given precedence. Travel between Labrador and the Island of Newfoundland is restricted to the Labrador Straits (Strait of Belle Isle). The seasonal ferry between Lewisporte and Happy Valley-Goose Bay is not considered a viable option for regular travel and solutions are not provided.
The Provincial Ferry Service should be consulted for seasonal, remote and island-community accessibility.

Procedures

The calculations of the NL-RDDb are produced using the
Network Analyst extension within the ESRI ArcGIS 10 ® environment. The road
network is developed based on a modified version of the provincial road network.
The communities’ points have been assigned to the approximate center of the
community based on a combination of satellite imagery and 1:50,000 scale maps.
In some cases, larger communities may also have various localities designated to
improve distance estimation, ex. Kilbride of St. John’s. Furthermore,
some points of interest have been added such as: National Parks, airports, ferry
terminals, and more.

Error Sampling

The results of the NL-RDDb have been compared
to the "Kilometer Guide" of the Department of Tourism - Traveler’s Map and
results produced by online mapping programs, such as Google Maps. Furthermore,
consultation with public/private transportation providers has helped to eliminate individual discrepancies on an on-going basis.

Minor discrepancies are expected within the NL-RDDb, however most are attributed to the use of a single point to
represent large area or ribbon developments. See Procedures for more
information on community representation. Most distance estimations are assumed
to be reasonably accurate; however there is typically some positional error
related with features in any GIS database. The goal of the NL-RDDb is to be +/-
2% accurate on all distances within the database. Travel time estimations are
based on the posted maximum speed limit on individual road segments within each
calculation. In some cases the posted maximum speed limit was
unavailable; estimations were made based on the road classification. Ferry
travel is based on 15 km/h rate of speed, and travel time estimates do not
account for individual ferry scheduling (for more information visit Provincial Ferry Service).

Disclaimer

The NL-RDDb is an extensive database and every effort
has made to provide the most current information, however we cannot guarantee all information is accurate and complete. For more information on
terms and conditions of the NL-RDDb, please refer to the Disclaimer.